Carburetor having auxiliary turbine and idle fuel shutoff mechanism

ABSTRACT

A carburetor for an internal combustion engine utilizes a rotatable air motor to achieve intimate mixing of fuel and air and hence provide a combustible mixture of enhanced burning qualities to the engine. The air motor utilizes a hollow, rotatable hub with fuel jets to deliver the fuel and a plurality of vanes to atomize the same. The air motor is driven by the flow of air through the air horn except when airflow is minimal (closed or nearly closed throttle positions). During this minimal airflow, the engine creates a suction head which is utilized to cause air to flow over a turbine that is coupled with the air motor, thereby rotating the turbine to, in turn, drive the motor. During deceleration, fuel is not required to be supplied to the engine and hence mechanism is provided to block the flow of fuel to the engine in response to closing of the engine throttle valve. The mechanism is also operable by the decrease in pressure caused by the suction head created when the engine descends a long steep grade and hence will continue to block the flow of fuel during such a descent as long as the throttle valve remains closed. Fuel is delivered to the air motor as a result of a suction conduit which has an outlet into the interior of the air horn. Thus, during the minimal airflow this fuel is atomized effectively by the rotation of the air motor and when fuel is not needed, the flow is completely shut off. When it is desirable to increase the quantity of fuel delivered to the air motor to meet the power requirements of the engine, one or more venturi boost rings are employed in the vicinity of the suction conduit outlet to increase the suction and hence the quantity of fuel delivered to the air motor.

United States Patent Rollins 15] 3,654,909 [451 Apr. 11, 1972 i541CARBURETOR HAVING AUXILIARY TURBINE AND IDLE FUEL SHUTOFF MECHANISM [72]Inventor: Eugene C. Rollins, PO. Box 1484, Ogden,

Utah 84402 [22] Filed: Aug. 6, 1970 21 Appl. No; 61,624

[52] U.S.Cl ..123/l4l R, 123/97 R, 123/1 19 R, 123/127 R, 261/41 R,261/83, 261/D1G. 12, 261/D1G. 41, 261/D1G. 19, 26l/DIG. 60

Primary Examiner-Wendell E. Burns Att0rneySchmidt, Johnson, Hovey &Williams [5 7] ABSTRACT A carburetor for an internal combustion engineutilizes a rotatable air motor to achieve intimate mixing of fuel andair and hence provide a combustible mixture of enhanced burningqualities to the engine. The air motor utilizes a hollow, rotatable hubwith fuel jets to deliver the fuel and a plurality of vanes to atomizethe same. The air motor is driven by the flow of air through the airhorn except when airflow is minimal (closed or nearly closed throttlepositions). During this minimal airflow, the engine creates a suctionhead which is utilized to cause air to flow over a turbine that iscoupled with the air motor, thereby rotating the turbine to, in turn,drive the motor. During deceleration, fuel is not required to besupplied to the engine and hence mechanism is provided to block the flowof fuel to the engine in response to closing of the engine throttlevalve. The mechanism is also operable by the decrease in pressure causedby the suction head created when the engine descends a long steep gradeand hence will continue to block the flow of fuel during such a descentas long as the throttle valve remains closed.

Fuel is delivered to the air motor as a result of a suction conduitwhich has an outlet into the interior of the air horn. Thus, during theminimal airflow this fuel is atomized effectively by the rotation of theair motor and when fuel is not needed, the flow is completely shut off.When it is desirable to increase the quantity of fuel delivered to theair motor to meet the power requirements of the engine, one or moreventuri boost rings are employed in the vicinity of the suction conduitoutlet to increase the suction and hence the quantity of fuel deliveredto the air motor.

32 Claims, 7 Drawing Figures PATENTEDAPR 11 I972 SHEET 3 [IF 3CARBURETOR HAVING AUXILIARY TURBINE AND IDLE FUEL SI-IUTOFF MECHANISMThis invention relates to carburetors for internal combustion enginesand, more particularly, to an improvement in a carburetor of the typeshown and described in U.S. Pat. No. 2,668,698, entitled Carburetor,which issued to the present applicant on Feb. 9, 1954.

Achieving proper mixture of fuel and air to provide the most highlycombustible mixture is extremely important in all internal combustionengines. A significant advance in the art is represented by theabove-referenced prior patent of the present applicant. A limitation ofthe carburetor of this prior patent however, is its inability to supplyfuel to an engine in the relatively wide range of quantities requiredfor modern high-performance engines. It has, in fact, been a limitationof prior carburetors in general that they do not have the wide range offuel delivery capacity required by modern automobile engines. This hasnecessitated the use of multistage carburetors which are relativelyexpensive and complex, both in their initial cost and to maintain.

Another deficiency of prior art carburetors is their tendency toover-supply engines with fuel. This results in only partial combustionof the fuel with a certain percentage of the same being dischargedthrough the engine exhaust as either partially burned or raw fuel. Thisis a major factor in the atmosphere pollution which is attributed toautomobile engines. The over supply of fuel occurs primarily duringdeceleration when the engine actually requires no fuel, but the same isstill supplied by the carburetor. Prior mechanical devices for keepingthe engine running at a high enough speed to burn some of the excessfuel are undesirable because they sustain the engine at an undesiredincreased speed and also because they do not reach the source of theproblem.

It is, therefore, an important object of the present invention toprovide a carburetor utilizing an air motor to atomize and distributefuel wherein relatively large motor bearings can be utilized, thuspermitting the fuel passage through the motor to be enlarged and therebyincrease the overall capacity of the carburetor.

As a corollary to the foregoing object it is an aim of the presentinvention to provide a carburetor with an increased fuel capacitythereby eliminating the need for relatively complex multistagecarburetors.

A further object of the invention is to provide a carburetor with anincreased fuel capacity which provides equal flow dis tribution betweenadjacent air passages of a two barrel carburetor, thereby allowing thetwo barrels to be fed from a single fuel metering and discharge device.

Another object of the present invention is to provide a carburetorwherein an air motor atomizes the fuel and means is provided forrotating the air motor at an increased speed to thereby achieve superioratomization of the fuel and hence, a more combustible mixture resultingin more efficient and more economical engine operation.

Yet another object of the invention is to provide a carburetor asdescribed in the foregoing object whereby the auxiliary means employedto rotate the air motor at increased speeds is particularly effective atlow engine loads when the passage of air through the carburetor isreduced and thus the speed of the rotation of the air motor wouldnormally be reduced.

As a corollary to the foregoing object, the present invention has as anaim the provision of turbine means for rotating the air motor, andwherein the turbine is caused to rotate by the flow of air past theturbine as a result of the increased suction head present in the engineduring low engine loads.

Another aim of the invention is to provide a boost venturi incombination with a carburetor as described in the foregoing objects todeliver fuel to the carburetor in larger quantities and thereby utilizethe latters increased capacity.

Another object of the present invention is to provide for an auxiliaryair supply to the engine when the throttle is completely closed, thusresulting in more complete fuel consumption and eliminating the gum anddeposits which would otherwise tend to build up in the throat of thecarburetor.

A very important object of the invention is also to provide mechanismfor blocking the flow of idle fuel to the engine when fuel is notrequired during deceleration, thus avoiding the discharge of unburnedand partially burned fuel from the engine exhaust.

A further object of the invention is to provide idle fuel shutoff meanswhich is responsive to both the initial throttle closing and the suctionhead of the engine created during long grade descents to assure that theflow of fuel will be blocked as long as the throttle valve remainsclosed.

An aim of the invention is also to provide mechanism for blocking theflow of fuel to the engine when fuel is not required during decelerationand thereby assuring a smooth transition from open throttle to curb idleby avoiding overloading the engine with fuel.

As a corollary to the above object, an aim of the invention is toprovide mechanism for controlling the fuel flow to the engine from openthrottle to engine idle which eliminates prior dashpot controls and doesnot require the engine to be sustained by mechanical devices at higherthan desired speeds.

In the drawings:

FIG. 1 is a cross-sectional view through the fuel compartment and theair horn of a carburetor constructed according to the teachings of thepresent invention with portions of the air motor having been removed forpurposes of illustration;

FIG. 2 is an enlarged, cross-sectional view through the air horn of thecarburetor and the air motor partially visible in FIG. 1 showing detailsof construction of the latter;

FIG. 3 is a cross-sectional view on a reduced scale taken along line 3-3of FIG. 2;

FIG. 4 is a partial vertical cross-sectional view similar to FIG. 2 andillustrating an alternative form of the invention wherein a plurality ofventuri boost rings are employed to fully utilize the increased fuelcapacity of the carburetor;

FIG. 5 is a horizontal, cross-sectional view through the walls of thecarburetor housing taken immediately above the bolt and nut visible inFIG. 4 with the impact tube visible in FIG. 4 being removed for purposesof illustration;

FIG. 6 is a horizontal, cross-sectional view illustrating an alternativeform for the air passage in which the air motor is disposed; and

FIG. 7 is a bottom plan view of the passage-defining housing illustratedin FIG. 6.

The present invention is best understood with reference to myabove-mentioned patent and the same is incorporated herein by referenceto the extent necessary to obtain a complete and full understanding ofthe present invention.

Referring initially to FIG. 2 of the drawings, an annular housing 10presents an air horn which defines a central air passage 12. The wallsof the housing 10 converge at 14 to provide a venturi constriction 16intermediate the ends of the air horn. An air motor, designatedgenerally by the numeral 18, is mounted within the venturi constriction16 by structure which includes an upper boss 20 secured to the housing10 by radially extending fins 22 and 24, and a lower boss 26 secured tothe housing 10 by a fin 28. A support member 30 positions a bearinghousing 32 in a central position within the lower boss 26. A secondbearing housing 34 is held in position within the upper boss 20 by acage 36 and a vertical support which includes a bolt 38, a coil spring40 and a nut 42. An O-ring seal 44 is held by the cage 36 for purposesto be made clear hereinafter. A plurality of bearings 46 and 48 aredisposed within the upper and lower bearing housings 34 and 32respectively, and rotatably support the air motor 18.

The air motor 18 includes a central, hollow, rotatable axle 50 whichsupports a hollow, rotatable hub 52 having a plurality of vanes 54, anda pair of opposed fuel jets 56 extending therefrom. The disposition ofthe vanes 54 relative to the fuel jets 56 is best illustrated in FIG. 2.An extension of the hollow axle 50 mounts a turbine comprising a secondrotatably hub 58 and a plurality of vanes 60 upwardly from the air motor18 in spaced relationship to the latter. A baffle 62 is disposed withinthe hollow axle 50 to direct fuel outwardly toward the fuel jets 56. Afuel passage is presented by an extension 64 of the support member 30and a bore 66 within the fin 28, the bore 66 communicating directly withthe fuel compartment 67 (FIG. 1). An opening 68 in the lower boss 26presents a fuel well which is in direct communication with the fuelpassage as a result of a plurality of openings in the extension 64.

An impact tube (not shown) directs air into a passage 70 whichcommunicates with the fuel compartment and air from the passage 70 isdirected into the aforementioned fuel passage through a conduit 72. Asexplained in the abovereferenced patent, a piston 74, coupled with anactuating rod 76, operates a needle valve (not shown) for controllingthe flow of fuel into the bore 66 during maximum engine powerrequirements. An air passage 78 communicates the area of the housingwithin which the piston 74 is disposed with the suction head created bythe engine by virtue of the outlet port 80 which opens into the interiorof the air horn below an engine throttle valve 81 (FIG. 1). The airpassage 78 communicates with the turbine presented by hub 58 and vanes60 as a result of passages 82 and 84 in the housing 10 and the fin 24respectively. Thus, the turbine means is also under the control of thesuction head of the engine as a result of the aforementioned passages.Control means in the nature of a screw valve 86 is selectivelypositionable within the juncture of passages 82 and 84 to control theairflow through the passages. A keeper spring 88 maintains a givensetting of the screw valve 86.

An impact tube 90 in the wall of the housing 10 opposite the passage 70directs air via a passage 92 to an auxiliary fuel jet 94. The fuel jet94 receives fuel during sudden acceleration as a result of a series ofvalves (not shown) operable by the throttle control mechanism asexplained in the referenced patent.

An opening 96 in the boss 20 communicates with appropriate openings inthe lower end of bolt 38 and the hollow axle 50 to present a suctionconduit in communication with the fuel passage presented by extension 64and bore 66. This suction conduit has an outlet port 98 which isdirectly opposite an outlet port 100 for a second suction conduitpresented by passages 102 and 104 in the housing 10 and the fin 22respectively. This second suction conduit communicates with the firstsuction conduit and, therefore, likewise with the fuel passage. Thirdand fourth suction conduits identical to the two mentioned above, but180 removed therefrom, are also normally provided in communication withthe fuel passage, but these have been omitted from FIG. 1 for clarity.Opening 96 and passage 102 which form a part of the third and fourthsuction conduits are, however, visible in FIG. 3.

Referring now to FIG. 1, the fuel compartment 67 presents a fuel storagearea 110 into which fuel is introduced through a connection 112. Theintroduction of fuel into the area 110 is controlled by a valve 114which is actuated by a float 116. The fuel compartment housing 67 alsodefines a chamber 118 which communicates with the fuel storage area 110through an interconnecting passage 120. The passage 120 is provided witha first ball check valve 122 which permits the flow of fuel into thepassage 120 through inlet passage 124 while blocking the flow of fuel inthe opposite direction, and a second ball check valve 126 which isbiased by a coil spring 128 to present a restricted outlet into the fuelstorage area through an outlet port 130. A portion of the passage 120 ispresented by a yieldable member in the form of a flexible diaphragm 132for purposes to be made clear hereinafter.

A plunger mechanism 134 is coupled with the throttle valve 81 through aconnecting rod 136, an operating rod 138, and an arm 140 which is anintegral part of the rod 138. The plunger mechanism 134 includes aflexible plunger cup 142 which is mounted at the base of an upstandingstem 144, the latter being surrounded by a coil spring 146. The arm 140is slidably received on the stem 144 and is biased away from the plungercup 142 by the spring 146.

As explained above, fuel is delivered to the air motor 18 of a fueldelivery conduit 152 which extends through an orifice-defining seat 154.As explained in the referenced patent, fuel is delivered through theconduit 152, a second conduit 156, and an interconnecting passage 158 todischarge ports 160 and 162 during idle operation of the engine. Thedischarge port 160 is just below the edge of the throttle valve 81 whenthe latter is in a closed position, and the flow of fuel to the engineunder these circumstances is determined by the needle valve 164 which isheld by a spring 166.

A pressure responsive structure is disposed for blocking the flow offuel in the conduit 152 and the fuel delivery bore 66 when the throttlevalve 81 is closed and the engine is operating at a sufficiently highspeed to cause a suction head of relatively large magnitude. Thisstructure includes a yieldable actuator member in the form of a flexiblediaphragm 168 which cooperates with a second diaphragm 170 to define apressure chamber therebetween. The pressure chamber is communicated withthe suction head of the engine by a branch 172 of the air passage 78.Yielding of the diaphragm 168 operates a valve member which includes anactuating rod 174 coupled with the diaphragm 168 and a needle valve 176which is supported by the diaphragm 132. A coil spring 178 maintains thevalve 176 in an open position and a coil spring 180 likewise maintainsthe actuating rod 174 in a raised position. A passageway 182communicates the area beneath the diaphragm 170 with the area 110 forpurposes to be made clear hereinafter. It will be appreciated that therod 174 is slidably received by an opening in the adjacent housing topermit the rod to engage the needle valve 176.

A shoulder 184 on the stem of the needle valve 176 provides a retainerfor a second valve in the form of a closure plate 186 which is slidablyreceived by the stem of the valve 176. A coil spring 188 biases theclosure plate 186 against the shoulder 184 which limits movement of theplate 186 in one direction.

It is, of course, to be appreciated that the suction head of the engineis minimal when the throttle valve 81 is in its wideopen position. Thisallows maximum flow of air through the passage 12, past the air motor 18and into the combustion chambers of the engine. This flow of air pastthe air motor 18 causes the latter to rotate. The flow of air throughthe passage 12 also creates a suction at the outlet ports 98 and 100which causes fuel to be drawn up through the fuel passage anddistributed outwardly to the rotating fuel jets 56. The baffle 62directs the flow of fuel radially outwardly to the jets 56. The vanes 54atomize the fuel as the latter is introduced into the air passage in amanner which is most effective in producing a fuel mixture of a morehighly combustible nature.

As the throttle valve is closed, the flow of air through the passage 12is reduced and the suction head created by the engine during operationis of an increasingly greater magnitude. Heretofore it has beennecessary to utilize a relatively small axle 50 for the air motor 18since the bearings 46 and 48 were necessarily of a relatively small sizein order to exhibit the highly frictionless qualities required tomaintain operation of the air motor 18 when the flow of air through thepassage 12 was reduced. This, in turn, limited the size of the fuelpassage which could be utilized to deliver fuel to the hollow hub 52.The overall capacity of the carburetor is, of course, determined by thesize of this fuel passage. In the present invention, bearings 46 and 48of a larger size can be utilized, thus accommodating a larger fuelpassage as a result of the turbine presented by hub 58 and vanes 60. Asthe suction head of the engine increases, an increasing suction ispresent at the outlet port 80 which communicates the auxiliary turbinewith the suction head of the engine through passages 78, 82 and 84.Thus, the suction headcauses airflow over the turbine rotating thelatter and thus effecting rotation of the air motor 18 at an increasedspeed over that which would be possible in the absence of the auxiliaryturbine. Not only is the air motor 18 maintained in operation when itwould not otherwise be possible because of the larger, more frictionalbearings 46 and 48, but the motor 18 is rotated at an increased speedthereby achieving better atomization of the fuel introduced into thecarburetor.

The suction created by the flow of air past the outlet port 98 issomewhat greater than would otherwise be the case, and thus the secondsuction conduit tends to equalize the different suctions at the outletports 98 and 100 with the effective suction acting upon the fuel passagebeing the average value of the suctions at the outlet ports 98 and 100.In some cases however, it may be desirable to omit the second suctionconduit. The O-ring seal 44 between the suction conduit and air passages78, 82 and 84 prevents air from being drawn past the cage 36 which woulddisturb the metering function of the suction conduits. Another importantadvantage of the present invention is the auxiliary air supply which isavailable during low engine loads when the flow of air through thepassage 12 is reduced, as a result of the suction at the outlet port 80which draws air over the turbine and through the passages 78, 82 and 84.It is desirable to have the vanes 60 pitched in a direction opposite thepitch of the vanes 54 to assure that the air motor will rotate in thesame direction whether it is being caused to rotate by the flow of airover the turbine or past the vanes 54. This is particularly importantduring sudden accelerations when the suction head of the engine ismomentarily increased prior to the increase in the flow of air throughthe passage 12. Thus, the auxiliary turbine gives the air motor aninitial boost before the increased airflow can reach the vanes 54. Bythis arrangement, the carburetor is much more responsive to suddenaccelerations. The flow of air over the auxiliary turbine is controlledby the degree to which the valve 86 extends into the air passages 82 and84. This, in turn, controls the speed of rotation of the air motor 18under conditions of relatively light engine loads when the suction headis causing air to flow over the turbine.

It will be appreciated that during deceleration, power is not requiredfrom the engine and it is desirable to block the flow of fuel throughthe idle discharge system under these circumstances. This isparticularly true when a vehicle is descending a long steep grade. Thus,when an operator moves the throttle valve to a closed position, the arm140 of the actuating rod 138 moves downwardly on the stem 144 againstthe action of the coil spring 146. As the plunger cup 142 is forceddownwardly by the action of the coil spring 146, it forces fuel from thechamber 118 and into the passage 120. The increased pressure in thepassage 120 which is magnified by the check valve 126, causes thediaphragm 132 to flex downwardly. This, in turn, moves the needle valve176 downwardly into engagement with the seat 154 to block the flow ofidle fuel into the conduit 152. The shoulder 184 is positioned relativeto the end of the needle valve to cause the closure plate 186 to beunseated from the shoulder 184 when the plate 186 engages the leadingedge of the orifice body 148. The plate 186 is biased into engagementwith the body 148 by the coil spring 188, thereby blocking the flow offuel to the air motor 18 through the fuel delivery bore 66. It will beappreciated that the closing of the valves 176 and 186 lags somewhatbehind the closing of the throttle valve 81. That is, closing of thevalve 81 first results in compression of the spring 146 which, uponsubsequent expansion, causes the increased pressure in the passage 120which, in turn, closes the valves 176 and 186. This is desirable toassure that the increased pressure in the passage 120 will be maintainedfor a short period after the throttle 81 is closed to thereby maintainthe valves 176 and 186 closed until the engine speed has had time toslow down to match the new throttle opening. The ball check valve 126and its associated spring 128 also facilitate maintaining an increasedpressure in the passage 120 for a longer period of time than wouldotherwise be possible.

Once all of the fuel has been forced from the chamber 118, the pressurein the passage 120 gradually returns to normal and, were it not for theactuator rod 174, the diaphragm 132 would return to its normal positionraising the valve 176 with it to again open the bore 66 and the conduit152 to the flow of fuel. HOwever, since the pressure chamber defined bythe diaphragms 168 and 170 is communicated with the suction head of theengine, as long as this suction head is maintained at a suflicientlyhigh level, a negative pressure will be acting upon the diaphragm 168.This negative pressure causes the diaphragm 168 to flex downwardly,moving the actuator rod 174 into engagement with the needle valve 176 tomaintain the latter closed regardless of the pressure in the passage120. Once the throttle valve 81 is again moved to an open position, thesuction head of the engine decreases in magnitude, thereby relieving thenegative pressure within the chamber between diaphragms 168 and 170 toallow the coil spring 180 to return the rod 174 to its raised positionwhich, in turn, allows the coil spring 178 to return the needle valve176 and the closure plate 186 to their open positions. It is to beunderstood of course, that the magnitude of the suction head of theengine is substantially greater when the engine is operating at arelatively high speed as the vehicle descends a long steep grade withthe throttle valve 81 closed than is the case when the throttle valve isclosed and the engine is operating at curb" idle. The diaphragm 168 isselected to allow flexing thereof in response to the relatively greatsuction head which occurs when the engine is operating at a relativelyhigh speed and when no fuel is required to be supplied thereto, but isof a size sufficient to preclude flexing under the influence of therelatively small suction head present during curb idle. Thus, the flowof fuel will not be cut off when it is required to keep the engineoperating at idle speeds.

As the throttle valve 81 is opened, the arm 140 is raised, carrying withit the plunger mechanism 134 and creating a suction in the chamber 118which draws fuel through the inlet 124 into the passage 120 to againfill the chamber 118 with fuel.

It is to be understood that the actuator rod 174 and its associatedpressure chamber are not essential to the functioning of the needlevalve 176 and can be deleted from the carburetor if desired. In suchcase, the valve 176 is opened and closed solely in response to flexingof the diaphragm 132 and the valve would not remain closed while theengine descended a long steep grade. With the actuator rod 174positioned above the needle valve 176, as is preferred, the opening inthe adjacent housing through which the actuator rod passes also providesa relief opening for fuel under excessive pressure within the passage120. Any fuel passing through this relief passage is free to flow backinto the storage area 110 through connecting passageway 182. It is alsoto be understood that while a double valve arrangement utilizing closureplate 186 and needle valve 176, is preferable from a design standpoint,a single closure valve could be utilized to block the conduit 152 andthe bore 66 which branches therefrom.

It will be appreciated that the fuel shutoff control mechanism not onlygives greater fuel economy and combustion efficiency but also eliminatesthe need for mechanical devices for maintaining the engine at anundesired increased speed while excess fuel is burned. The result is amuch smoother transition of the engine to an idle speed.

Referring now to the alternative form of the invention illustrated inFIGS. 4 and 5, an upper boss 220 of generally rectangular cross sectionis utilized in cooperation with the lower boss 26 to mount the air motor18 within the air horn presented by the housing 10. A suction conduit192 extends upwardly toward the leading edge of the boss 220 to presentan outlet port 194 into the air passage 212. The suction conduit 192communicates with the fuel passage through bolt 38 and hollow axle 50 inthe same manner as described in the preferred embodiment for the suctionconduits presented by opening 96 and passages 102 and 104. An airdirector member in the nature of an annular body 196 of sharplydecreasing cross-sectional dimension presents a boost venturi and isspaced from the outlet port 194 in surrounding relationship to the boss220. A second annular body 198 also of sharply decreasingcross-sectional dimension, has an inside diameter greater than theoutside diameter of the annular body 196 and is spaced downwardly fromthe latter with the edge of smallest mately 180 removed from the conduit192, although this second conduit has been omitted from FIG. 4 forclarity. The outlet port 194 of the second suction conduit is, however,visible in FIG. 5.

Operation of the alternative form of the invention is identical to theoperation of the preferred embodiment previously described. However, thepresence of the venturi boost rings 196 and 198 creates an increasedsuction at the ports 194 and 194 as air flows through the passage 12.This increased suction draws fuel through the fuel passage and into thehollow, rotatable hub 52 at an increased rate, thereby effectivelyutilizing the increased capacity of the carburetor.

Referring now to a further modification of the invention which isillustrated in FIGS. 6 and 7, an annular housing 310 presents an airhorn which defines a central air passage 312 within which the air motor18 is mounted by bosses 20 and 26, the latter being supported byradially extending fins 24 and 28. The lower end of the housing 310flares outwardly and is integral with the fin 28 to present a pair ofadjacent air passages 200 and 202 disposed beneath the air motor 18.

Operation of the air motor 18 and the associated idle fuel shutoffcontrol mechanism is the same with the embodiment illustrated in FIGS. 6and 7 as for the other embodiments previously described. The air hornpresented by passage 310 is, however, designed to be used with a typicalV-6 or V-8 engine having a pair of cylinder banks, the passages 200 and202 communicating directly with the respective cylinder banks. Althoughheretofore it has not been practical to deliver fuel to both barrels ofa two-barrel carburetor from a single fuel metering and dischargesystem, because there was no assurance that there would be equal flow toeach of the two barrels, this is now possible with the air motor 18since the latter inherently gives an equal flow distribution to bothbarrels. It will be appreciated that the modified form of the inventionillus trated in FIGS. 3 and 4 and described above has equalapplicability to the two-barrel carburetor of FIGS. 6 and 7.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. In a carburetor for use with an internal combustion engine thatcreates a suction head during operation, said carburetor having an airhorn and a rotatable air motor mounted within the air horn, thecombination with said air motor of:

turbine means coupled with said air motor for sustaining operation ofthe latter at an increased speed of rotation when the flow of air pastthe air motor is reduced; and

means defining an air passage communicating with said turbine means andadapted to be communicated with said suction head to cause airflow overthe turbine means to rotate the latter, whereby to effect rotation ofsaid air motor at said increased speed.

2. The invention of claim 1, and

means selectively positionable within said air passage for controllingthe airflow over said turbine and hence the speed of rotation of thelatter, whereby to control the speed of rotation of said air motor.

3. The invention of claim 1,

said air horn being provided with a venturi constriction,

said air motor having a hollow, rotatable hub, a plurality of vanesdisposed around the hub, and fuel delivery means in communication withthe hub;

means defining a fuel passage in communication with said hub; and

means defining a suction conduit in communication with said fuel passageand presenting an outlet port into the air horn at said venturiconstriction, whereby the suction created by the passage of air throughthe air horn draws fuel through said fuel passage and into said hollowhub.

4. The invention of claim 3,

said turbine means including a second hollow, rotatable hub coaxial withthe first-mentioned rotatable hub, spaced from the latter, and having aplurality of vanes disposed therearound,

said suction conduit extending through said second rotatable hub.

5. The invention of claim 3, and

structure mounting said air motor within the venturi constriction,

said structure and said air horn defining a second suction conduit incommunication with said first suction conduit and presenting an outletport into the air horn in opposed relationship to the first-mentionedsuction conduit outlet port, whereby the suction drawing fuel throughsaid fuel passage is the average suction at the first and second suctionconduit outlet ports.

6. The invention of claim 3,

said suction conduit being disposed adjacent said air passage; and

sealing means separating said suction conduit from said air passage.

7. The invention of claim 3, and

an air director member within the air horn spaced from said outlet portand presenting a boost venturi for drawing air from said outlet port andthrough said suction conduit whereby fuel is drawn through the fuelpassage and into the hollow hub of the air motor as a result of the flowof air through said air horn and past said boost venturi.

8. The invention of claim 7,

said carburetor being adapted for use with an engine of the kind havinga pair of cylinder banks,

said carburetor having a pair of air passages communicating with the airhorn and each adapted for communication with a corresponding cylinderbank.

9. The invention of claim 1,

said air motor and said turbine means having a common axis of rotation;and

means intercoupling said air motor and said turbine means for rotationin unison in the same direction.

10. The invention of claim 1,

said air motor including an axle having an extension and a hub securedto the axle and provided with a plurality of vanes therearound,

said turbine means being rigidly mounted on said extension.

1 l. The invention of claim 1,

said carburetor being adapted for use with an engine of the kind havinga pair of cylinder banks,

said carburetor having a pair of air passagescommunicating with the airhorn and each adapted for communication with a corresponding cylinderbank.

12. In a carburetor:

an air horn provided with a venturi constriction;

a rotatable air motor mounted within the horn and having a hollow hub;

means defining a fuel passage in communication with said hub;

means defining a suction conduit in communication with said passage andhaving an outlet port into the horn; and

an air director member within the horn spaced from said port andpresenting a boost venturi for drawing air from said port and throughsaid conduit, whereby fuel is drawn through the passage and into the hubas a result of the flow of air through said horn and past said boostventuri.

13. The invention of claim 12,

said member having a surface facing the port, said surface divergingfrom the port in the direction of airflow.

14. The invention of claim 13, and

a second annular body having a surface facing the port,

said surface of the second body diverging from the port in the directionof airflow, said second body having an inside diameter greater than theoutside diameter of the firstmentioned body,

said second body being spaced downwardly from the firstmentioned bodywith the edge of smallest cross-sectional dimension of the latter beingadjacent the area of greatest cross-sectional dimension of the latter.

15. In a carburetor for an internal combustion engine that creates asuction head during operation, said carburetor ineluding a fuelcompartment, a throttle valve for controlling the flow of fuel from saidcompartment to the engine, and a conduit for delivering idle fuel fromthe compartment to the engine when said valve is in a closed position,the combination with said carburetor of idle fuel shutoff meanscomprising:

a chamber;

a passage interconnecting the chamber and the compartment formaintaining a supply of fuel in the chamber; mechanism operably coupledwith said valve for forcing fuel from said chamber and into the passagein response to movement of the valve toward the closed position;structure in said passage yieldable to the pressure of fuel forced intothe passage; and means responsive to the yielding of said structure forblocking the flow of fuel in said conduit from said compartment to theengine.

16. The invention of claim 15, wherein said structure comprises adiaphragm which presents a portion of said passage.

17. The invention of claim 16, wherein said responsive means comprises avalve coupled with said diaphragm; and yieldable means for biasing saidvalve into an open position.

18. The invention of claim 15, and first and second check valves withinsaid passage, said first check valve being disposed to block the flow offluid from the passage while allowing the flow of fuel into the latterfrom said compartment, said second check valve being disposed to presenta restricted orifice by which fuel flowing through the passage from thechamber is discharged into said compartment.

19. The invention of claim 15, wherein said mechanism includes a plungerand an operating rod for actuating said plunger.

20. The invention of claim 19, wherein said plunger is pro vided with anupstanding stem, said operating rod is slidably received on said stern;and yieldable means acting against said operating rod to bias the latteraway from the plunger.

21. The invention of claim 15, wherein the carburetor conduit isbranched to present a fuel-conveying bore for delivering fuel to theengine, and said responsive means includes a first valve coupled withsaid structure for blocking the conduit below said bore, and a secondvalve coupled with said structure for blocking the conduit above saidbore.

22. The invention of claim 21, wherein said first valve comprises aneedle valve coupled with said structure, and said second valvecomprises a closure plate mounted on said needle valve.

23. The invention of claim 22, and first yieldable means biasing saidneedle valve into an open position, said closure plate being slidablymounted on said needle valve; there being retainermeans on said needlevalve for limiting sliding movement of said closure plate in onedirection; and second yieldable means biasing said closure plate againstsaid retainer means.

24. The invention of claim 15, including a pressure responsive actuatorfor operating said responsive means independently of the yielding ofsaid structure; and means defining an air passage communicating saidactuator with the suction head of the engine whereby the actuatoroperates said responsive means to cause the latter to block the flow offuel in the conduit in response to the decrease in pressure caused bythe suction head of the engine.

25. The invention of claim 24, wherein said actuator includes a pressurechamber at least partially defined by a yieldable member, and anactuating rod coupled with said member, said air passage communicatingwith said pressure chamber.

26. In a carburetor for use with an internal combustion engine thatcreates a suction head during operation,-said carburetor having an airhorn, a rotatable air motor mounted within the air horn, a fuelcompartment, a throttle valve for controlling the flow of fuel from saidcompartment to the engine, and a conduit for delivering idle fuel fromthe compartment to the engine when said valve is in a closed position,the combination with said carburetor of:

turbine means coupled with said air motor for sustaining operation ofthe latter at an increased speed of rotation when the flow of air pastthe motor is reduced;

means defining an air passage communicating with said turbine means andadapted to be communicated with said suction head to cause airflow overthe turbine means to rotate the latter;

a chamber;

a passage interconnecting the chamber and the compartment formaintaining a supply of fuel in the chamber; mechanism operably coupledwith said valve for forcing fuel from said chamber and into the passagein response to movement of the valve toward the closed position;structure in said passage yieldable to the pressure of fuel into thepassage; and means responsive to the yielding of said structure forblocking the flow of fuel in said conduit from said compartment to theengine.

27. The invention of claim 26, and

an air director member within the air horn spaced from said outlet portand presenting a boost venturi for drawing air from said outlet port andthrough said suction conduit whereby fuel is drawn through the fuelpassage and into the hollow hub of the air motor as a result of the flowof air through said air horn and past said boost venturi.

28. In a carburetor for use with an internal combustion engine thatcreates a suction head during operation, said carburetor having an airhorn, a rotatable air motor mounted within the air horn, a fuelcompartment, a throttle valve for controlling the flow of fuel from saidcompartment to the engine, and a conduit for delivering idle fuel fromthe compartment to the engine when said valve is in a closed position,the combination with said carburetor of:

turbine means coupled with said air motor for sustaining operation ofthe latter at an increased speed of rotation when the flow of air pastthe motor is reduced; pressure responsive means for blocking the flow offuel in said conduit from said compartment to the engine; and

means defining an air passage communicating said pressure responsivemeans and said turbine means with said suction head to cause airflowover the turbine means to rotate the latter and said pressure responsivemeans to block the flow of fuel in said conduit in response to thedecrease in pressure caused by the suction head.

29. The invention of claim 28,

said carburetor being adapted for use with an engine of the kind havinga pair of cylinder banks,

said carburetor having a pair of air passages communicating with the airhorn and each adapted for communication with a corresponding cylinderbank.

30. In a carburetor for use with an internal combustion engine thatcreates a suction head during operation, said carburetor having an airhorn, a rotatable air motor mounted within the air horn, a fuelcompartment, a throttle valve for controlling the flow of fuel from saidcompartment to the engine, and a conduit for delivering idle fuel fromthe compartment to the engine when said valve is in a closed position,the combination with said carburetor of:

turbine means coupled with said air motor for sustaining operation ofthe latter at an increased speed of rotation when the flow of air pastthe motor is reduced;

a chamber;

a passage interconnecting the chamber and the compartment formaintaining a supply of fuel in the chamber; mechanism operably coupledwith said valve for forcing fuel from said chamber and into the passagein response to movement of the valve toward a closed position;

structure in said passage yieldable to the pressure of fuel forced intothe passage;

means responsive to the yielding of said structure for blocking the flowof fuel in said conduit from said compartment to the engine;

a pressure responsive actuator for operating said responsive meansindependently of the yielding of said structure; and

means defining an air passage communicating said actuator and saidturbine means with said suction head whereby the actuator operates saidresponsive means to cause the latter to block the flow of fuel in theconduit and air flows over said turbine means to rotate the latter, bothin response to the decrease in pressure caused by the suction head.

'In'IA 31. The invention of claim 30,

said carburetor being adapted for use with an engine of the kind havinga pair of cylinder banks,

said carburetor having a pair of air passages communicating with the airhorn and each adapted for communication with a corresponding cylinderbank.

32. The invention of claim 31, and

an air director member within the air horn spaced from said outlet portand presenting a boost venturi for drawing air from said outlet port andthrough said suction conduit whereby fuel is drawn through the fuelpassage and into the hollow hub of the air motor as a result of the flowof air through said air horn and past said boost venturi.

1. In a carburetor for use with an internal combustion engine thatcreates a suction head during operation, said carburetor having an airhorn and a rotatable air motor mounted within the air horn, thecombination with said air motor of: turbine means coupled with said airmotor for sustaining operation of the latter at an increased speed ofrotation when the flow of air past the air motor is reduced; and meansdefining an air passage communicating with said turbine means andadapted to be communicated with said suction head to cause airflow overthe turbine means to rotate the latter, whereby to effect rotation ofsaid air motor at said increased speed.
 2. The invention of claim 1, andmeans selectively positionable within said air passage for controllingthe airflow over said turbine and hence the speed of rotation of thelatter, whereby to control the speed of rotation of said air motor. 3.The invention of claim 1, said air horn being provided with a venturiconstriction, said air motor having a hollow, rotatable hub, a pluralityof vanes disposed around the hub, and fuel delivery mEans incommunication with the hub; means defining a fuel passage incommunication with said hub; and means defining a suction conduit incommunication with said fuel passage and presenting an outlet port intothe air horn at said venturi constriction, whereby the suction createdby the passage of air through the air horn draws fuel through said fuelpassage and into said hollow hub.
 4. The invention of claim 3, saidturbine means including a second hollow, rotatable hub coaxial with thefirst-mentioned rotatable hub, spaced from the latter, and having aplurality of vanes disposed therearound, said suction conduit extendingthrough said second rotatable hub.
 5. The invention of claim 3, andstructure mounting said air motor within the venturi constriction, saidstructure and said air horn defining a second suction conduit incommunication with said first suction conduit and presenting an outletport into the air horn in opposed relationship to the first-mentionedsuction conduit outlet port, whereby the suction drawing fuel throughsaid fuel passage is the average suction at the first and second suctionconduit outlet ports.
 6. The invention of claim 3, said suction conduitbeing disposed adjacent said air passage; and sealing means separatingsaid suction conduit from said air passage.
 7. The invention of claim 3,and an air director member within the air horn spaced from said outletport and presenting a boost venturi for drawing air from said outletport and through said suction conduit whereby fuel is drawn through thefuel passage and into the hollow hub of the air motor as a result of theflow of air through said air horn and past said boost venturi.
 8. Theinvention of claim 7, said carburetor being adapted for use with anengine of the kind having a pair of cylinder banks, said carburetorhaving a pair of air passages communicating with the air horn and eachadapted for communication with a corresponding cylinder bank.
 9. Theinvention of claim 1, said air motor and said turbine means having acommon axis of rotation; and means intercoupling said air motor and saidturbine means for rotation in unison in the same direction.
 10. Theinvention of claim 1, said air motor including an axle having anextension and a hub secured to the axle and provided with a plurality ofvanes therearound, said turbine means being rigidly mounted on saidextension.
 11. The invention of claim 1, said carburetor being adaptedfor use with an engine of the kind having a pair of cylinder banks, saidcarburetor having a pair of air passages communicating with the air hornand each adapted for communication with a corresponding cylinder bank.12. In a carburetor: an air horn provided with a venturi constriction; arotatable air motor mounted within the horn and having a hollow hub;means defining a fuel passage in communication with said hub; meansdefining a suction conduit in communication with said passage and havingan outlet port into the horn; and an air director member within the hornspaced from said port and presenting a boost venturi for drawing airfrom said port and through said conduit, whereby fuel is drawn throughthe passage and into the hub as a result of the flow of air through saidhorn and past said boost venturi.
 13. The invention of claim 12, saidmember having a surface facing the port, said surface diverging from theport in the direction of airflow.
 14. The invention of claim 13, and asecond annular body having a surface facing the port, said surface ofthe second body diverging from the port in the direction of airflow,said second body having an inside diameter greater than the outsidediameter of the first-mentioned body, said second body being spaceddownwardly from the first-mentioned body with the edge of smallestcross-sectional dimension of the latter being adjacent the area ofgreatest cross-sectioNal dimension of the latter.
 15. In a carburetorfor an internal combustion engine that creates a suction head duringoperation, said carburetor including a fuel compartment, a throttlevalve for controlling the flow of fuel from said compartment to theengine, and a conduit for delivering idle fuel from the compartment tothe engine when said valve is in a closed position, the combination withsaid carburetor of idle fuel shutoff means comprising: a chamber; apassage interconnecting the chamber and the compartment for maintaininga supply of fuel in the chamber; mechanism operably coupled with saidvalve for forcing fuel from said chamber and into the passage inresponse to movement of the valve toward the closed position; structurein said passage yieldable to the pressure of fuel forced into thepassage; and means responsive to the yielding of said structure forblocking the flow of fuel in said conduit from said compartment to theengine.
 16. The invention of claim 15, wherein said structure comprisesa diaphragm which presents a portion of said passage.
 17. The inventionof claim 16, wherein said responsive means comprises a valve coupledwith said diaphragm; and yieldable means for biasing said valve into anopen position.
 18. The invention of claim 15, and first and second checkvalves within said passage, said first check valve being disposed toblock the flow of fluid from the passage while allowing the flow of fuelinto the latter from said compartment, said second check valve beingdisposed to present a restricted orifice by which fuel flowing throughthe passage from the chamber is discharged into said compartment. 19.The invention of claim 15, wherein said mechanism includes a plunger andan operating rod for actuating said plunger.
 20. The invention of claim19, wherein said plunger is provided with an upstanding stem, saidoperating rod is slidably received on said stem; and yieldable meansacting against said operating rod to bias the latter away from theplunger.
 21. The invention of claim 15, wherein the carburetor conduitis branched to present a fuel-conveying bore for delivering fuel to theengine, and said responsive means includes a first valve coupled withsaid structure for blocking the conduit below said bore, and a secondvalve coupled with said structure for blocking the conduit above saidbore.
 22. The invention of claim 21, wherein said first valve comprisesa needle valve coupled with said structure, and said second valvecomprises a closure plate mounted on said needle valve.
 23. Theinvention of claim 22, and first yieldable means biasing said needlevalve into an open position, said closure plate being slidably mountedon said needle valve; there being retainer means on said needle valvefor limiting sliding movement of said closure plate in one direction;and second yieldable means biasing said closure plate against saidretainer means.
 24. The invention of claim 15, including a pressureresponsive actuator for operating said responsive means independently ofthe yielding of said structure; and means defining an air passagecommunicating said actuator with the suction head of the engine wherebythe actuator operates said responsive means to cause the latter to blockthe flow of fuel in the conduit in response to the decrease in pressurecaused by the suction head of the engine.
 25. The invention of claim 24,wherein said actuator includes a pressure chamber at least partiallydefined by a yieldable member, and an actuating rod coupled with saidmember, said air passage communicating with said pressure chamber. 26.In a carburetor for use with an internal combustion engine that createsa suction head during operation, said carburetor having an air horn, arotatable air motor mounted within the air horn, a fuel compartment, athrottle valve for controlling the flow of fuel from said compartment tothe engine, and a conduit for delivering idle fuel from the compartmentto the enginE when said valve is in a closed position, the combinationwith said carburetor of: turbine means coupled with said air motor forsustaining operation of the latter at an increased speed of rotationwhen the flow of air past the motor is reduced; means defining an airpassage communicating with said turbine means and adapted to becommunicated with said suction head to cause airflow over the turbinemeans to rotate the latter; a chamber; a passage interconnecting thechamber and the compartment for maintaining a supply of fuel in thechamber; mechanism operably coupled with said valve for forcing fuelfrom said chamber and into the passage in response to movement of thevalve toward the closed position; structure in said passage yieldable tothe pressure of fuel into the passage; and means responsive to theyielding of said structure for blocking the flow of fuel in said conduitfrom said compartment to the engine.
 27. The invention of claim 26, andan air director member within the air horn spaced from said outlet portand presenting a boost venturi for drawing air from said outlet port andthrough said suction conduit whereby fuel is drawn through the fuelpassage and into the hollow hub of the air motor as a result of the flowof air through said air horn and past said boost venturi.
 28. In acarburetor for use with an internal combustion engine that creates asuction head during operation, said carburetor having an air horn, arotatable air motor mounted within the air horn, a fuel compartment, athrottle valve for controlling the flow of fuel from said compartment tothe engine, and a conduit for delivering idle fuel from the compartmentto the engine when said valve is in a closed position, the combinationwith said carburetor of: turbine means coupled with said air motor forsustaining operation of the latter at an increased speed of rotationwhen the flow of air past the motor is reduced; pressure responsivemeans for blocking the flow of fuel in said conduit from saidcompartment to the engine; and means defining an air passagecommunicating said pressure responsive means and said turbine means withsaid suction head to cause airflow over the turbine means to rotate thelatter and said pressure responsive means to block the flow of fuel insaid conduit in response to the decrease in pressure caused by thesuction head.
 29. The invention of claim 28, said carburetor beingadapted for use with an engine of the kind having a pair of cylinderbanks, said carburetor having a pair of air passages communicating withthe air horn and each adapted for communication with a correspondingcylinder bank.
 30. In a carburetor for use with an internal combustionengine that creates a suction head during operation, said carburetorhaving an air horn, a rotatable air motor mounted within the air horn, afuel compartment, a throttle valve for controlling the flow of fuel fromsaid compartment to the engine, and a conduit for delivering idle fuelfrom the compartment to the engine when said valve is in a closedposition, the combination with said carburetor of: turbine means coupledwith said air motor for sustaining operation of the latter at anincreased speed of rotation when the flow of air past the motor isreduced; a chamber; a passage interconnecting the chamber and thecompartment for maintaining a supply of fuel in the chamber; mechanismoperably coupled with said valve for forcing fuel from said chamber andinto the passage in response to movement of the valve toward a closedposition; structure in said passage yieldable to the pressure of fuelforced into the passage; means responsive to the yielding of saidstructure for blocking the flow of fuel in said conduit from saidcompartment to the engine; a pressure responsive actuator for operatingsaid responsive means independently of the yielding of said structure;and means defining an air passage communicating said actuator and saidturbine means with said suction head whereby the actuator operates saidresponsive means to cause the latter to block the flow of fuel in theconduit and air flows over said turbine means to rotate the latter, bothin response to the decrease in pressure caused by the suction head. 31.The invention of claim 30, said carburetor being adapted for use with anengine of the kind having a pair of cylinder banks, said carburetorhaving a pair of air passages communicating with the air horn and eachadapted for communication with a corresponding cylinder bank.
 32. Theinvention of claim 31, and an air director member within the air hornspaced from said outlet port and presenting a boost venturi for drawingair from said outlet port and through said suction conduit whereby fuelis drawn through the fuel passage and into the hollow hub of the airmotor as a result of the flow of air through said air horn and past saidboost venturi.